YEAH, BUT MEASURED FROM WHERE TO WHERE?
From Gay City News:

In writer/director Ramón Salazar's eye-popping comedy-musical-romance, the title "20 Centimeters," refers to the length of Marieta's penis. Marieta (Mónica Cervera), born Aldolfo, is a narcoleptic, pre-op transsexual prostitute who is saving her money to get her 8.78+ inches turned into a vagina, but various friends and lovers complicate her life, delaying her from realizing her dream.

Maybe it's just me, but I think 8.78 inches is specific enough without adding the "plus". You're really not going to notice the extra 0.002 inches of manhood, are you?

You don't see me walking around discussing my 3.699999, do you? No, you don't. Because I don't make things that difficult. I simplify things by rounding up.

To 7.